The invention relates to a sheet film changer comprising a photographic exposure station, at least one supply magazine for the film sheets, and two discrete, synchronously driven conveyor belts which are guided over rollers, and which are disposed one on top of the other for conveying the film sheets, clamped between them, from a receiving location associated with the supply magazine, to the photographic exposure station, and to a release location.
In the German Pat. No. 1,140,064, a sheet film changer is described wherein the individual film sheets, clamped between two conveyor belts, are conveyed from a supply magazine to a photographic exposure station, and from the photographic exposure station again back to a collector magazine via a shunt.
The conveyor belts bearing against the film sheet on both sides are coated with intensifier material on the surfaces facing the film sheet. At their two ends, they are each respectively wound up on a take-up roller. In the case of this sheet film changer, it is considered a disadvantage that only X-ray photographs can be prepared with the latter. Alone due to the as-specified-high absorption value of the intensifier material, but also due to the contact surface in the photographic exposure station, there is no possibility of installing an X-ray image intensifier and of transilluminating the examination area for fluoroscopy. For the purpose of fluoroscopy, the entire sheet film changer must be replaced by an image intensifier-television system. The examination cycle is thereby interrupted, and the alignment with the examination subject is lost.
From the German Auslegeschrift No. 2,031,386, an X-ray examination apparatus is known with which fluoroscopy can be carried out as well as with which, as needed, X-ray photographs can be produced. To this end, however, the particularly protective transport of the film sheets between conveyor belts enclosing the same on all sides is dispensed with. In addition, a special film carriage must be utilized which transports the film sheets, as required, into the photographic exposure position in front of the X-ray image intensifier.